Present filling methods for underground storage tanks involve parking a tank truck adjacent to a fill pipe of the storage tank, and then attaching a flexible delivery hose leading from the tank truck's control panel to a liquid tight fitting at an accessible upper end of the underground storage tank's fill pipe. A liquid, such as gasoline is pumped into the storage tank until the operator ceases the filling operation or the tank fills completely and an automatic shut-off valve shuts off the pump system. There is always the possibility that a substantial amount of gasoline will be trapped in the delivery hose, up to about thirty-five gallons. Without special precautions being taken this trapped gasoline may be carelessly spilled onto the ground with the consequent possibility of earth and water contamination.
It is apparent that container means of some type must be provided for handling of the liquids trapped in a delivery hose. Various overflow tank and auxiliary holding tank systems are known in the prior art. Examples of these are disclosed in U.S. Pat. Nos. 3,983,913; 4,204,564; and 4,501,305. One drawback all the disclosed systems have is the inflexibility and consequent difficulty of the tank truck operator being able to connect the delivery hose to the fill pipe's attachment fitting. Most delivery hoses are bulky; additionally, known overflow systems have a hinged lid which extends upward when opened. The result is that a large surface opening must be provided for access to the hinged lid and the operator must position his tank so that the hinged lid does not block entry of the delivery hose to the fill pipe's fitting.
The development of the present invention provides ready access to a fill pipe for an underground storage tank. The development also provides a means for retaining gasoline that a delivery hose contains after its fill function has been completed. The excess trapped gasoline is emptied into a dump truck, which is either automatically drained or manually drained into the storage tank as gasoline is pumped from the storage tank in normal service station operation.